After the August introduction of Hatsune Miku, Crypton produced a young male and female duet follow-up with vocaloids Rin and Len - both based on the voice of Asami Shimoda (Idolmaster's Ami and Mami Futami). According to Asami Shimoda, Len's voice was achieved by singing within her chest, while Rin's at the top of her head. Shimoda has also confirmed that they're named for Fist of the North Star hero Kenshiro and his young sidekick Rin.
Sega is marking their December 27th birthday with a special Project Diva F trailer:
"Tokyo Teddy Bear" and "Yumekui Shirokuro Baku" will be included as a third of the new songs added to Project Diva F - the PlayStation 3 version of the currently available in Japan PS Vita game Project Diva f.